Hydraulically-operated shoring apparatus with pressure safety lock



Aug. 15, 1967 E. T. WARD HYDRAULICALLY-OPERATED SHORING APPARATUS WITHPRESSURE SAFETY LOCK 2 Sheets-Sheet 1 Filed July 27, 1965 kw WTTO/QA/CVQm w w m Aug. 15, 1967 E. T. WARD 3,335,573

HYDRAULICALLY-OPERATE D SHORING APPARATUS WITH PRESSURE SAFETY LOCKFiled July 27, 1965 2 Sheets-Sheet 27 INVENTOR. EU6M 7? W'QO 26 5 IV J Mw W ABSTRACT OF THE DHSCLOSURE Collapsible shoring in which shoringrails are forced against opposite trench walls by a hydraulic jackcylinder expanded by a disconnectable pressure line to a cylinder base;an external fitting on the base maintains cylinder pressure when theline is disconnected. An internal failsafe check valve in series withthe fitting maintains cylinder pressure if the fitting is damaged duringuse but is operable by means (preferably a lever normally protected by acylinder wall from accidental operation) to open the check valve whenpressure relief is required to collapse the shoring.

This invention relates to hydraulically-operated apparatus for shoringthe sides of trenches dug in unstable soils, such as sandy soils.

Heretofore, various hydraulic jack parallelogram arrangements have beenused for shoring the sides of such trenches. In one such arrangement, apair of horizontally disposed, vertically spaced, hydrauliccylinder-and-piston units are connected pivotally at their opposite endsto plate-like shoring rails which extend upright against the oppositesides of the trench. In another type, a pair of horizontally disposed,horizontally spaced, hydraulic cylinder-and-piston units are connectedpivotally at their opposite ends to horizontal shoring rails which abutagainst conventional shoring timbers or planks at the opposite sides ofthe trench. In both types of such apparatus, the cylinder-and-pistonunits are cross braces extending across the trench. After theparallelogram is inserted in the trench, hydraulic liquid is pumped intothe cylinders to force the respective pistons to extend positions untilthe shoring rails are jacked apart to the desired extent.

In certain types of such shoring apparatus the respectivecylinder-and-piston cross braces are connected at their opposite ends tohinge blocks, which are pivotally connected to the respective shoringrails. One hinge block, at the cylinder end of a cross brace, has aninlet fitting for connection to an inlet hose which passes hydraulicliquid under pressure from the pump. This inlet fitting, of knowndesign, includes a check valve which is held open while the inlet hoseis connected, permitting hydraulic liquid to flow from the pump intothat hinge block and from there to the cylinder. When the inlet hose isdisconnected, this check valve in the inlet fitting closes to preventhydraulic liquid from flowing out of the cylinder.

While the shoring apparatus is in shoring position in the trench, withits cylinders under hydraulic pressure, the inlet fitting may be brokenoff of the hinge block if it is struck by a digging tool or the like. Inthat event, there is nothing to prevent hydraulic liquid from spillingout of the cylinder, so that the shoring apparatus would no longer shoreup the sides of the trench. The present invention is directed to a novelsafety lock for preventing this.

Accordingly, it is a principal object of this invention to provide anovel safety lock for a hydraulically-operated States Patent shoringapparatus to prevent the accidental loss of hydraulic pressure in thelatter.

Further objects and advantages of this invention will be apparent fromthe following detailed description of a presently-preferred embodimentthereof, which is illustrated in the accompanying drawings.

In the drawings:

FIGURE 1 is a perspective view showing a hydraulic jack parallelogramshoring apparatus on which the present safety lock is provided;

FIGURE 2 is an enlarged fragmentary perspective view showing the presentsafety lock on the hinge block at the cylinder end of one of thecylinder-and-piston cross braces in the FIG. 1 apparatus;

FIGURE 3 is an enlarged view, partly in elevation and partly in section,showing part of this hinge block and the present safety lock thereon,with the operating lever removed; and

FIGURE 4 is a section taken along the line 4-4 in FIG. 3, with theoperating lever added.

Referring to FIG. 1, the shoring apparatus shown therein comprises apair of horizontal shoring rails 10 and 11 for engagement respectivelywith conventional shoring planks or timbers 12 at the opposite sides ofthe trench. Shoring rail 10 pivotally supports a pair of hinge blocks 13and 14, as does the opposite shoring rail 11. The hinge blocks 13 and 14on shoring rail 10 are rigidly connected threadedly to respectivecylinders 15 and 16. These cylinders slidably receive respective pistons(not shown) carrying piston rods 17 and 18 for connection to therespective hinge blocks (not shown) pivoted on the opposite shoring rail11. Each cylinder-and-piston unit is a hydraulic cross brace. These twohydraulic cross braces and the shoring rails 10, 11, to which they arepivotally connected by the hinge blocks, together make up a hydraulicjack parallelogram.

Referring to FIG. 4, the hinge block 13 has a screwthreaded opening 19,which threadedly receives one end of cylinder 15, and an internalpassageway communicating with this opening for passing hydraulic liquidinto and out of cylinder 15.

Hinge block 13 has a screw-threaded inlet opening 20. An inlet fitting21 (FIG. 2) of known design is mounted in this opening. This inletfitting has a check valve which is arranged to be held open as long as ahose (not shown) is attached to it, which takes place while theparallelogram is being jacked into place against the shoring planks.Afterwards, when the inlet hose is detached, this check valve staysclosed so as to prevent the escape of hydraulic liquid from cylinder 15.

In accordance with the present invention, a second check valve 22 (FIG.4) is provided between the cylinder 15 and the inlet fitting 21. Thisadditional check valve 22 comprises a sleeve-like body 23 seated in arecess 24 in the hinge block 13 between a passage 25 connected to theinlet opening 20 and a passage 26 leading into the cylinder 15. AnO-ring seal 27 is provided between the valve body 23 and the wall ofthis hinge block recess 24. This valve body has an opening 28 at itsupper end in FIG. 4, a frusto-conical valve seat 29 just beyond thisopening, and a longitudinal passage 30 between valve seat 29 and thehinge block passage 26 leading to cylinder 15.

Check valve 22 also includes reciprocable valve member 31 inside valvebody 23- and carrying a rubber ring 32 for sealing engagement with valveseat 29. A coil spring 33 is engaged under compression between valvemember 31 and a stamping 34 carried by the valve body 23. Normally, thisspring biases valve member 31 to a closed position, in which the rubberring 32 sealingly engages the valve seat 29 to prevent fluid flowbetween opening 28 and passage 30, as shown in FIG. 4. In this 3position, the front end nose 35 of valve member 31 projects beyond thevalve body 23.

An annular body 36 is seated in the hinge block 13 with its inner endabutting against the front end of valve body 23, surrounding the lattersopening 28. This body 36 carries an O-ring 37 which sealingly engagesthe wall of a bore 38 in the hinge block. The inlet passage 25 in thehinge block intersects this bore, and the inner end of body 36 hasopenings 39 for passing liquid between passage 25 and the opening 28 invalve body 23.

Body 36 has an annular flange 40 which is received in a counterbore 41in the front of hinge block 13. A clamping plate 42, which is heldagainst the front face of hinge block 13 by a pair of screws 43, 44,engages the outer end face of this body flange 40. Body 36 presents apair of opposite ears 45, 46 (FIG. 2), which extend through arectangular opening 57 in plate 42 to the front of hinge block 13. Theseears support a pivot pin 47 for an operating lever 48. This lever isadapted to extend away from the front of hinge block 13, presenting atransverse handle 49 adapted to rest on top of cylinder 15, as shown inFIGS. 1 and 2. As shown in FIG. 2, the clearance between cars 45, 46 andthe opening 57 in plate 42 is sufiiciently close to prevent anysubstanit-al rotation of body 36 on its own longitudinal axis. Thisinsures that the pivot pin 47 for lever 48 will be horizontal, as shownin FIG. 2.

At its opposite, pivoted end the lever 48 has a cam 50. This cam has aminimum radius along the longitudinal axis of lever 48 (i.e., directlytoward the hinge block 13 in FIG. 2) and a progressively increasingradius in a counterclockwise direction in FIG. 2 upward from thelongitudinal axis of lever 48.

A plunger 51 (FIG. 4) is slidable in the body 36. The outer end face 52of this plunger engages the cam 50 on lever 48. At its inner end thisplunger presents an enlarged head 53 for engagement with the front endnose 35 of valve member 31. Plunger 51 carries an O-ring 54 Whichsealingly engages the wall of the bore 55 in body 36.

Plate 42 has a projecting tooth 56 (FIG. 3) for engagement in acomplementary recess in cylinder to lock the latter in hinge block 13.

When the lever 48 extends substantially horizontal, with its handle 49overlying the cylinder 15, as shown in FIGS. 1 and 2, the minimum radiuspart of the cam 50 is engaging the plunger 51. Under this condition,spring 33 will maintain check valve 22 closed, as shown in FIG. 4.

However, when the user pivots the lever 48 to a vertical upstandingposit-ion (indicated in phantom in FIG. 2), this will move theprogressively larger radius surface of cam 50 over the plunger 51 toforce the plunger inwardly so as to unseat valve member 31 in checkvalve 22.

While the cylinder 15 is being filled from the pump, the lever 48 may bein its horizontal position. The pressure of the hydraulic liquiddelivered by the pump will open the check valve 22 and also will forcethe plunger 51 outward to the position shown in FIG. 4. When the pump isstopped, check valve 22 will close under the urging of its spring 33. Itwill remain closed to prevent backfiow from the cylinder 15 even if theinlet fitting 21 is broken off, in which event the check valve in theinlet fitting would no longer be effective to prevent such backfiow.Check valve 22 is completely disposed within the hinge block 13 so thatany blow which might disable the check valve in the inlet fitting 21normally will not also disable check valve 22.

When the user wishes to empty the cylinder, in addi tion to opening thecheck valve in fitting 21 by connecting a hose to it, he will turn thelever 48 to its upright position, causing cam 50 to force plunger 51inwardly to unseat the valve member 31 in check valve 22.

In the particular shoring apparatus shown in FIG. 1, the hinge block 14at the cylinder end of the other cross brace is identical in allrespects, including the safety control, to the arrangement justdescribed. With such apparatus two separate hose connections areprovided, one for each cross brace. However, it is to be understood thatthe present invention also may be embodied in shorting apparatus inwhich the two cylinder-end hinge blocks are interconnected by a hose andonly one of them has an inlet fitting, so that the two cylinders may bepressurized or emptied simultaneously through a single hose connected tothis inlet fitting.

Accordingly, it is to be understood that, while a presently-preferredembodiment of this invention has been described in detail herein withreference to the accompanying drawings, the invention is susceptible toother embodiments differing structurally from the particular embodimentshown.

I claim:

1. In a hydraulic jack parallelogram for shoring the opposite sides of"a trench or the like and comprising a pair of opposite shoring rails; apair of cylinder-andpiston cross braces, each including a cylinder and apiston slidable therein; means coupling each piston pivotally to one ofsaid shoring rails; and a pair of hinge blocks pivotally connecting therespective cylinders to the opposite shoring rail, at least one of saidhinge blocks having an inlet fitting for connection to a hose and apassageway between said inlet fitting and the respective cylinder, saidinlet fitting having provision for preventing the escape of hydraulicliquid from said cylinder when the hose is detached; the improvementwhich comprises:

a normally-closed check valve in said passageway to prevent the escapeof liquid from the respective cylinder if said inlet fitting isdisabled, and means for selectively holding said check valve open topermit the withdrawal of hydraulic liquid from said cylinder.

2. In a hydraulic jack parallelogram for shoring the opposite sides of atrench or the like and comprising a pair of opposite shoring rails; apair of cylinder-andpiston cross braces, each including a cylinder and apiston slidable therein; means coupling each piston pivotally to one ofsaid shoring rails; and a pair of hinge blocks pivotally connecting therespective cylinders to the opposite shoring rail, at least one of saidhinge blocks having an inlet fitting for connection to a hose and apassageway between said inlet fitting and the respective cylinder, saidinlet fitting having normally-closed valve means for preventing theescape of hydraulic liquid from said cylinder when the hose is detached;the improvement which comprises:

a normally-closed check valve in said passageway to prevent the escapeof liquid from the respective cylinder if said inlet fitting isdisabled, an operating lever pivotally supported from said one hingeblock, and means acting between said lever and said check valve foropening said check valve in response to a predetermined movement of saidlever.

3. In a hydraulic jack parallelogram for shoring the opposite sides of atrench or the like and comprising a pair of opposite shoring rails; 21pair of cylinder-and-piston cross braces, each including a cylinder and-a piston slidable therein; means coupling each piston pivotally to oneof said shoring rails; and a pair of hinge blocks pivotally connectingthe respective cylinders to the opposite shoring rail, at least one ofsaid hinge blocks having an inlet fitting for connection to a hose and apassageway between said inlet fitting and the respective cylinder, saidinlet fitting having normally-closed valve means for preventing theescape of hydraulic liquid from said cylinder when the hose is detached;the improvement which comprises:

a normally-closed check valve in said passageway to prevent the escapeof liquid from the respective cylinder if said inlet fitting isdisabled, said check valve being completely disposed within said onehinge block, an operating lever pivotally supported from said one hingeblock and extending therefrom along the cylinder and having a handleresting on the cylinder, said lever having a cam at its pivoted end, anda plunger slidably disposed in the hinge block between the cam on thelever and said check valve, said plunger being engageable by the cam tomove inward to open said check valve in response to pivotal movement ofthe lever toward an upright position.

4. In a hydraulic jack parallelogram for shoring the opposite sides of atrench or the like and comprising a pair of opposite shoring rails; 31pair of cylinder-andpiston cross braces, each including a cylinder and apiston slidable therein; means connecting each piston pivotally to oneof said shoring rails; and a pair of hinge blocks pivotally connectingthe respective cylinders to the opposite shoring rail, at least one ofsaid hinge blocks having an inlet fitting for connection to a hose and apassageway between said inlet fitting and the respective cylinder, saidinlet fitting having normally-closed valve means for preventing theescape of hydraulic liquid from said cylinder when the hose is detached;the improvement which comprises:

a normally-closed check valve in said passageway to prevent the escapeof liquid from the respective cylinder if said inlet fitting isdisabled, said check valve being completely disposed within said onehinge block, a hollow body seated in said one hinge block in front ofsaid check valve and presenting spaced ears at the front of said onehinge block, a pivot pin supported by said ears, an operating lever onsaid pin extending therefrom along the respective cylinder and having ahandle resting on the cylinder, said lever having a cam at its pivotedend, and a plunger slid-ably disposed in said body between said cam onthe lever and said check valve, said plunger being engageable by saidcam to move inward along said body to open the check valve in responseto pivotal movement of the lever toward an upright position.

DAVID J. WILLIAMOWSKY, Primary Examiner.

JACOB SHA'PIRO, Examiner.

1. IN A HYDRAULIC JACK PARALLELOGRAM FOR SHORING THE OPPOSITE SIDES OF ATRENCH OR THE LIKE AND COMPRISING A PAIR OF OPPOSITE SHORING RAILS; APAIR OF CYLINDER-ANDPISTON CROSS BRACES, EACH INCLUDING A CYLINDER AND APISTON SLIDABLE THEREIN; MEANS COUPLING EACH PISTON PIVOTALLY TO ONE OFSAID SHORING RAILS; AND A PAIR OF HINGE BLOCKS PIVOTALLY CONNECTING THERESPECTIVE CYLINDERS TO THE OPPOSITE SHORING RAIL, AT LEAST ONE OF SAIDHINGE BLOCKS HAVING AN INLET FITTING FOR CONNECTION TO A HOSE AND APASSAGEWAY BETWEEN SAID INLET FITTING AND THE RESPECTIVE CYLINDER, SAIDINLET FITTING HAVING PROVISION FOR PREVENTING THE ESCAPE OF HYDRAULICLIQUID FROM SAID CYLINDER WHEN THE HOSE IS DETACHED; THE IMPROVEMENTWHICH COMPRISES: A NORMALLY-CLOSED CHECK VALVE IN SAID PASSAGEWAY TOPREVENT THE ESCAPE OF LIQUID FROM THE RESPECTIVE CYLINDER IT SAID INLETFITTING IS DISABLED, AND MEANS FOR SELECTIVELY HOLDING SAID CHECK VALVEOPEN TO PERMIT THE WITHDRAWAL OF HYDRAULIC LIQUID FROM SAID CYLINDER.